One day a ninja, samurai or sumo wrestler was hungry while working out in the rice paddies or as a geisha (whatever they do over there) and realized how wonderful it must be to live in America and while inspired by that vision invented noodles that could be eaten after being soaked in hot water.

Eventually some greedy bastard decided to add other stuff to it, but since they don't have the bounty that America has, they used vegetables and tiny bits of stray dogs and cats to complete their "Happy Fun-Time America Dream Soup!" (instant noodles original name).